1. Field of the Invention
The present invention relates to a water-type dispersion composition, and, especially to a water-type dispersion composition which has excellent storage stability, adhesion, alkali resistance, organic chemical resistance, weather resistance, hot water resistance, pollution recuperative characteristics, and the like and which is capable of forming a transparent and extremely hard film. The present invention also relates to a process for preparing this water-type dispersion composition.
2. Description of the Background Art
Coating agents are conventionally used in various field and the fields of application of these coating agents are steadily expanding. With this expansion, the characteristics required for these coating agents have advanced. There have been recent demands for coating agents which exhibit highly balanced performances in adhesion, chemical resistance, moisture resistance, weather resistance, hot water resistance, pollution recuperative characteristics, and the like and which are capable of forming an extremely hard film.
As coating agents partially satisfying such a demand, a composition including a partial condensation product of organosilane, colloidal silica dispersion liquid, and silicon-modified acrylic resin is disclosed (see Japanese Patent Application Laid-open No. 135465/1985). Also, a composition including a partial condensation product of organosilane, chelate compound of zirconium alkoxide, and a vinyl resin containing a hydrolytic silyl group is proposed (see Japanese Patent Application Laid No. 1769/1989).
However, these coating agents are all solvent types. Recently, there has been a strong demand for eliminating the use of solvents in view of low environmental pollution, resource saving, safety, sanitation, and the like. Therefore, use of these solvent-type coating agents is being eliminated in preference of aqueous coating agents.
Extensive studies have been conducted to develop reaction-type resin emulsions among these aqueous coating agents since these reaction-type resin emulsions are expected to improve performance such as water resistance, chemical resistance, and the like. Among these reaction-type resin emulsions, resin emulsions including a hydrolytic silyl group are proposed. A reaction-type resin emulsion including a vinyl polymer containing a hydrolytic silyl group and an amineimide group is disclosed in Japanese Patent Application Laid-open 26035/1995 as an example of such a resin emulsion including a hydrolytic silyl group. Also, an aqueous paint composition comprising a water dispersion composition of a vinyl polymer having an alkoxysilyl group and a water-type dispersion composition of a tin compound is disclosed in Japanese Patent Application Laid-open No. 91510/1995.
However, these resin emulsions containing a hydrolytic silyl group have inferior storage stability. If this emulsion is stored for a long period of time, there is the drawback that it gels and a paint film obtained from the emulsion after long time storage differs in characteristics from a paint film obtained from the emulsion directly after production and hence a stable quality cannot be maintained, causing problems in practice. Also, even when the storage stability is relatively high, these resin emulsions exhibit inferior balance in total performance including adhesion, chemical resistance, moisture resistance, weather resistance, hot water resistance, pollution recuperation characteristics, and the like.
The present invention has been achieved in view of these problems. It is an object of the present invention to provide a water-type dispersion composition which has extremely excellent storage stability, excellent balance in performance such as adhesion, alkali resistance, organic chemical resistance, moisture resistance, weather resistance, hot water resistance, pollution recuperation characteristics, and the like, allows a transparent and extremely hard paint film to be formed, and is useful as a coating agent.